American political science is a congenitally unsettled discipline, witnessing a number of movements designed to reorient its fundamental character. Four prominent movements are compared here: the statism accompanying the discipline's early professionalization, the pluralism of the late 1910s and early 1920s, behavioralism, and the Caucus for a New Political Science (with a brief glance at the more recent Perestroika). Of these movements, only the first and third clearly succeeded. The discipline has proven very hard to shift. Despite the rhetoric that accompanied behavioralism, both it and statism were revolutions without enemies within the discipline (other than those appearing after they succeeded), and therein lies the key to their success.